STMICROELECTRONICS STC4054GR

STC4054
800mA Standalone linear Li-Ion
Battery charger with thermal regulation
Feature summary
■
Programmable charge current up to 800mA
■
No external MOSFET, sense resistors or
blocking diode required
■
Constant current / constant voltage operation
with thermal regulation to maximize charge
rate without risk of overheating
■
Charges single cell li-ion batteries directly from
USB port
■
Preset 4.2V charge voltage with 1% accuracy
■
Automatic recharge
■
Single charge status output pin
■
Charge current monitor output for gas gauging
■
C/10 Charge termination
■
25µA supply current in shutdown mode
■
Low battery voltage detect for precharge
setting
■
Soft-start limits inrush current
■
TSOT23-5L package
required and its ThinSOT package make it ideally
suited for portable applications.
The STC4054 is designed to work within USB
power specifications. An internal block regulates
the current when the junction temperature
increases, in order to protect the device when it
operates in high power or high ambient
temperature.
Applications
■
Cellular telephones
■
PDAs
■
Bluetooth applications
■
Battery-powered devices
TSOT23-5L
Description
The STC4054 is a constant current/constant
voltage charger for single cell Li-Ion batteries. No
external sense resistor or blocking diode is
The charge voltage is fixed at 4.2V, and the
charge current limitation can be programmed
using a single resistor connectd between PROG
pin and GND. The charge cycle is automatically
terminated when the current flowing to the battery
is 1/10 of the programmed value. If the external
adaptor is removed, the STC4054 turns off and a
2µA current can flow from the battery to the
device. The device can be put into Shutdown
Mode, reducing the supply current to 25µA. The
device also has a charge current monitor, under
voltage lockout, automatic recharge. The device is
packaged in TSOT23-5L.
Order code
Part number
Package
Packaging
STC4054GR
TSOT23-5L
3000 parts per reel
September 2006
Rev. 1
1/17
www.st.com
17
STC4054
Contents
1
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2
Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5
Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6
Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.1
Charge cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.2
VCC Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.3
Power ON pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.4
CHRG pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.5
PROG pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.6
Programming charge current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.7
BAT pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.8
Charge termination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.9
Automatic recharge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.10
Soft start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
6.11
Thermal regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
6.12
Power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
6.13
Stability considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
8
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2/17
STC4054
Block diagram
1
Block diagram
Figure 1.
Block diagram
3/17
Pin configuration
STC4054
2
Pin configuration
Figure 2.
Pin connections (top view)
Table 1.
Pin description
Pln N°
Symbol
1
CHRG
2
GND
Ground pin
3
BAT
This pin provides an accurate 4.2V output voltage and the charge current to the battery.
Only 2µA reverse current can flow in to the device when in Shutdown mode
4
VCC
Input Supply voltage. The input range is from 4.25V to 6.5V. If VCC<VBAT+30mV the
device enters Shutdown mode and the sinked IBAT is less than 2µA
5
PROG
Figure 3.
4/17
Note
Open Drain. This pin goes in low impedance when the STC4054 is in precharge or
charge mode
Charge current program. Charge Current monitor and Shutdown pin
Application circuit
STC4054
Maximum ratings
3
Maximum ratings
Table 2.
Absolute maximum ratings
Symbol
Parameter
Value
Unit
VCC
Input supply voltage
From -0.3 to 10
V
VBAT
BAT pin voltage
From -0.3 to 7
V
VPROG
PROG pin voltage
From -0.3 to VCC+0.3
V
VCHRG
CHRG pin voltage
From -0.3 to 7
V
BAT pin current
800
mA
PROG pin current
800
µA
IBAT
IPROG
BAT short circuit duration
PD
Power dissipation
TJ
Max junction temperature
Continuous
Internally Limited
mW
125
°C
TSTG
Storage temperature range
-65 to 125
°C
TOP
Operating junction temperature range
-40 to 85
°C
Table 3.
Symbol
Thermal Data
Parameter
Value
Unit
RthJC
Thermal resistance junction-case
81
°C/W
RthJA
Thermal resistance junction-ambient
255
°C/W
5/17
Electrical characteristics
STC4054
4
Electrical characteristics
Table 4.
Electrical characteristics
(VCC = 5V, CI = 1µF, TJ = -40 to 85° unless otherwise specified) (Note 1).
Symbol
VCC
ICC
Parameter
Test
Supply voltage
IBAT
BAT pin current
IPRE
Pre-charge current
VPRE
Pre-charge threshold
VUV
VCC Undervoltage lockout
VMSD
VASD
6.5
V
500
Standby mode (charge terminated)
150
300
RPROG not
connected
21
40
VCC < VBAT
17
50
VCC < VUV
17
40
4.158
4.2
4.242
V
Current mode RPROG=10KΩ
90
100
110
mA
Current mode RPROG=2KΩ
465
500
535
mA
Standby mode VBAT=4.2V
0
-2.5
-6
µA
Shutdown mode (RPROG not
connected), TJ=25°C
±1
±2
µA
Sleep mode, VCC=0V, TJ=25°C
±1
±2
µA
VCC = 4.3V to 6.5V, RPROG =10KΩ
20
45
70
mA
RPROG =10KΩ VBAT falling
2.8
2.9
3.0
V
Hysteresis RPROG =10KΩ
70
100
130
mV
VCC Low to High RPROG =10KΩ
3.7
3.8
3.9
V
Hysteresis RPROG =10KΩ
50
180
300
mV
PROG Pin Rising
1.15
1.21
1.30
PROG Pin Falling
0.85
0.95
1.05
VCC Low to High TJ=25°C
RPROG =10KΩ
50
85
120
VCC High to Low TJ=25°C
RPROG =10KΩ
5
Manual shutdown threshold
VCC-VBAT Lockout threshold
µA
VBAT<2.8V RPROG =2KΩ TJ=25°C
V
mV
30
C/10 Termination current
threshold (IBAT/IBATC10)
(Note 3)
RPROG =10KΩ
0.1
RPROG =2KΩ
0.1
VPROG
PROG pin voltage
Current Mode RPROG =10KΩ
ICHRG
CHRG Pin current weak
pull-down
VCHRG=5V, VBAT=4.3V,
RPROG =10KΩ
VCHRG
CHRG Pin pull-down
voltage
ICHRG=5mA
6/17
Unit
150
ITERM
∆VRECHRG
Max.
Charge mode, RPROG =10KΩ,
VBAT = 3.5V
Supply current (Note 2)
Termination output voltage
Typ.
4.25
Shutdown mode
VBAT
Min.
50
mA/mA
Recharger battery threshold VFLOAT-VRECHRG, TJ=25°C
voltage
RPROG =10KΩ
0.93
1.0
1.07
V
8
20
35
µA
0.35
0.6
V
200
mV
STC4054
Table 4.
Electrical characteristics
Electrical characteristics
(VCC = 5V, CI = 1µF, TJ = -40 to 85° unless otherwise specified) (Note 1).
Symbol
Parameter
Test
Min.
Typ.
Max.
Unit
TLIM
Junction temperature in
constant current mode
120
°C
RON
Power Fet “ON” resistance
(Between VCC and BAT)
600
mΩ
tSS
Soft-start time
IBAT=0 to IBAT=1000V/RPROG
100
µs
Recharge comparator filter
time Note 4
VBAT High to Low
0.75
2
4.5
ms
tTERM
Termination comparator
filter time Note 4
IBAT Falling Below ICHG/10
400
1000
2500
µs
IPROG
PROG pin pull-up current
TRECHARGE
Note:
1
µA
1
The STC4054 was tested using a battery simulator and an output capacitor value about
4.7µF
2
Supply current includes PROG pin current but not include any current delivered to the
battery through the VBAT pin
3
ITERM is expressed as a fraction of measured full charge current with indicated PROG
resistor
4
Guaranteed by design
7/17
Typical performance characteristics
STC4054
5
Typical performance characteristics
Figure 4.
IBAT vs Supply voltage
Figure 5.
VBAT vs VCC
Figure 6.
IBAT vs temperature
Figure 7.
VPROG vs temperature
Figure 8.
IBAT/IPROG vs temperature
Figure 9.
IBAT vs VPROG
8/17
STC4054
Typical performance characteristics
Figure 10. IBAT/IPROG vs VCC
Figure 11. VCHRG vs temperature (CHRG pin
output low voltage)
Figure 12. ICHRG vs temperature (CHRG pin
weak pull down current)
Figure 13. Power FET “ON” resistance
Figure 14. IBAT vs VBAT
Figure 15. Recharge battery threshold voltage
vs. temperature
9/17
Application information
6
STC4054
Application information
The STC4054 uses an internal P-Channel MOSFET to work in constant current and
constant voltage method. It is able to provide up to 800mA with a final regulated output
voltage of 4.2V ± 1% in full temperature range. No blocking diode and sensing resistor are
required. It is also possible to use an USB port as power supply voltage.
6.1
Charge cycle
A charge cycle begins when the voltage at the VCC pin rises above the UVLO threshold
level, the RPROG program resistor of 1% is connected between the PROG pin to GND pin
and when a battery is connected to the charger output. If the battery voltage is below 2.9V,
the charger enters in Trickle Charge mode. In this condition, the device supplies 1/10 of the
programmed charge current to bring the battery voltage up to safe level otherwise the life of
a battery is reduced. If the BAT pin voltage is higher than 2.9V the charger enters in
Constant Current Mode. When the BAT pin voltage is close to the final float voltage (4.2V)
the device enters in Constant Voltage Mode and the charge current begins to decrease. The
charge cycle is terminated when the current drops to 1/10 of the programmed value.
6.2
VCC Pin
Input Supply Voltage. This pin is used to supplie the device in the range from 4.25V to 6.5V
voltage. A bypass capacitor of 1µF is recommended for use. When VCC value drops of
30mV of the BAT pin voltage, the device enters in Shutdown Mode, dropping IBAT to less
than 2µA.
6.3
CHRG pin
This is a flag open drain. It indicates three different status of the output. When the charge is
in progress this pin is pulled low instead at the end of the charge cycle, a weak pull down of
approximately 20µA is connected to the CHRG pin, indicating a present supply power; if the
flag is forced high impedance an under voltage condition is detected.
6.4
PROG pin
Charge Current Program, Charge Current Monitor and Shutdown Pin. The charge current is
programmed by connecting a 1% resistor, RPROG, to ground. When the device is charging in
constant current, the value of voltage on this pin is 1.0V. In other conditions, the voltage on
this pin can be used to measure the charge current using the following formula:
IBAT = (VPROG/RPROG)*1000
The PROG pin is used to shut down the device, disconnecting the program resistor from
ground a 1µA current flows to pull the PROG pin high. If the value of this Pin is 1.21V
(shutdown threshold voltage), the device enters Shutdown mode and the input supply
current drops to 25µA. Driving this pin to voltage beyond 2.4V a current of 35µA flows into
the device from PROG pin.
10/17
STC4054
6.5
Application information
Programming charge current
The RPROG resistor is used to set the charge current value. The battery charge current is
1000 times the Prog pin current value. The program resistor and the charge current are
calculated using the following formula:
RPROG=1000*VPROG/IBAT;
The charge current out of the BAT pin can be monitored through the PROG pin voltage
using the following equation:
IBAT=(VPROG/RPROG)x1000
6.6
Charge status indicator (CHRG)
The charge status output has three different states: Strong pull-down (~10mA), weak pulldown (20µA) and high impedance. The strong pull-down indicates that the device is
charging the battery. Weak pull-down indicates that VCC meets the UVLO conditions and the
device is ready to charge. The last status high impedance indicates an insufficient voltage is
applied to the VCC pin or the voltage on VCC is less than 100mV above the BAT pin voltage.
6.7
BAT pin
Charge Current Output pin. It provides charge current to the battery and regulates the final
float voltage to 4.2V. An internal precision resistor is used as a feedback loop to compare
the VO with the reference.
6.8
Charge termination
A charge cycle is terminated when the final float voltage is reached consequently the charge
current falls to 1/10th of the programmed value. The charge is over when the PROG pin
voltage falls below 100mV for longer time than tTERM (~1ms). The charge current is latched
off, the device enters in standby mode and the input supply current drops to 200µA.
6.9
Automatic recharge
The device restarts the charge cycle when the battery voltage falls below 4.05V to maintain
the battery capacity value higher than 80%. During the recharge time, the CHRG pin goes
low state.
6.10
Soft start
When a charge cycle starts, a internal soft start circuit minimizes the inrush current. At
starting phase, the charge current ramps from zero to the full scale in a 100µs period time.
11/17
Application information
6.11
STC4054
Thermal regulation
An internal thermal feedback loop reduces the output current if the die temperature attempts
to rise above a present value of approximately 120°C. This feature protects the device from
excessive temperature and allows the user to push the limits of the power handling
capability of a given circuit board without risk of damaging the device.
6.12
Power dissipation
It is very important to use a good thermal PC board layout to maximize the available output
current. The thermal path for the heat generated by the IC is from the die to the copper lead
frame through the package leads and exposed pad to the PC board copper. The PC board
copper is the heat sink. The footprint copper pads should be as wide as possible and
expand out to larger copper areas to spread and dissipate the heat to the surrounding
ambient. Feed through vias to inner or backside copper layers are also useful in improving
the overall thermal performance of the device. Other heat sources on the board, not related
to the device, must also be considered when designing a PC board layout because they will
affect overall temperature rise and the maximum output current.
6.13
Stability considerations
The STC4054 contains two control loops: constant voltage and constant current. The
constant-voltage loop is stable without any compensation when a battery is connected with
low impedance leads. Excessive lead length, however, may add enough series inductance
to require a bypass capacitor of at least 1µF from BAT to GND. Furthermore, a 4.7µF
capacitor with a 0.2Ω to 1Ω series resistor from BAT to GND is required to keep ripple
voltage low when the battery is disconnected.
12/17
STC4054
7
Package mechanical data
Package mechanical data
In order to meet environmental requirements, ST offers these devices in ECOPACK®
packages. These packages have a Lead-free second level interconnect. The category of
second Level Interconnect is marked on the package and on the inner box label, in
compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an ST trademark.
ECOPACK specifications are available at: www.st.com.
13/17
Package mechanical data
STC4054
TSOT23-5L MECHANICAL DATA
mm.
mils
DIM.
MIN.
TYP
A
MAX.
MIN.
TYP.
MAX.
1.1
43.3
3.9
A1
0
0.1
A2
0.7
1.0
27.6
39.4
b
0.3
0.5
11.8
19.7
C
0.08
0.2
3.1
7.9
D
2.9
114.2
E
2.8
110.2
E1
1.6
63.0
e
0.95
37.4
e1
1.9
74.8
L
0.3
0.6
11.8
23.6
7282780B
14/17
STC4054
Package mechanical data
Tape & Reel SOT23-xL MECHANICAL DATA
mm.
inch
DIM.
MIN.
TYP
A
MAX.
MIN.
TYP.
180
13.0
7.086
C
12.8
D
20.2
0.795
N
60
2.362
T
13.2
MAX.
0.504
0.512
14.4
0.519
0.567
Ao
3.13
3.23
3.33
0.123
0.127
0.131
Bo
3.07
3.17
3.27
0.120
0.124
0.128
Ko
1.27
1.37
1.47
0.050
0.054
0.0.58
Po
3.9
4.0
4.1
0.153
0.157
0.161
P
3.9
4.0
4.1
0.153
0.157
0.161
15/17
Revision history
STC4054
8
Revision history
Table 5.
Revision history
Date
Revision
04-Sep-2006
1
16/17
Changes
Initial release.
STC4054
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17/17